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using shunt with ADE7953 Demo Board is giving large error readings, please help me!

Question asked by Godson1 on Jul 6, 2017
Latest reply on Aug 25, 2017 by Godson1

dlath Please I was using CT before and now using shunt resistor, I have configured the ADE7953 EVAL board as directed in the UG-194. I used shunt resistor of 200microOhms. on the board there is no way to bypass the 51ohms burden resistor, so I removed it. I used the filter circuit of 1K resistor with 0.033microFarads capacitor. pls kindly attend to the challenges I'm facing using shunt, I look forward to reading from you. 

Here are my configuration values and error readings.

  • default reading ( without calibration) are:

error reading at

  1.  50A is 3.9909 at p.f of 1, and 9..0542 at p.f of 0.5L
  2.  5A is 1.6528 at p.f of 1, and 2.6420 at p.f of 0.5L
  3.  0.05A is -4.6647 at p.f of 1
  •  reading ( after AWGAIN calibration) are

error reading at

  1.  50A is 0.9670 at p.f of 1, and 0.5543 at p.f of 0.5L
  2.  5A is -0.0284 at p.f of 1, and -1.6135 at p.f of 0.5L
  3.  2.5A is -0.7582 at p.f of 1, and -3.1289 at p.f of 0.5L
  4.  0.5A is -7.0258 at p.f of 1, and -16.128 at p.f of 0.5L

 reading ( after PHACAL and AWGAIN calibration)  it gives correct accuracy at 5A, p.f of 1 and  0.5L. 

  • After offset,PHACAL,AWGAIN calibration, the reading at 5A  is 1.018. at p.f of 1 and 1.6584 at p.f of 0.5L

my question goes does; 

  1. what am i doing wrong ?
  2. how do i solve this problem?
  3. i discovered that after some time the reading goes higher again, does temperature affects the accuracy of the metering IC?
  4. culled from the AN118 "Do not perform offset calibration with grounded inputs because a low level signal is necessary to accurately measure the offset." explain this pls? because i am using shunt and its single ended. from the configuration, the phase is connected to ground.

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